SparkFun Electronics Commentsurn:uuid:214d0e4e-f1b1-d287-ce26-ac5b4c9f82492018-02-21T22:11:21-07:00SparkFun Electronicsbboyho on DEV-11590 - LilyTwinkle ProtoSnapbboyhourn:uuid:99649a74-fe61-5ab7-8f73-16d8f80cde542017-04-26T13:37:53-06:00<p><strong>&mdash;&mdash;&mdash;&mdash;&mdash;&mdash;&ndash; Tech Support Tips/Troubleshooting/Common Issues &mdash;&mdash;&mdash;&mdash;&mdash;&mdash;&ndash;</strong></p>
<p><strong>Reprogramming the ATTiny85 on the LilyTwinkle</strong></p>
<p>You can reprogram the ATtiny85 on the board if you have a AVR Programmer and adapter. Try looking at these instructions for more information [ <a href="https://learn.sparkfun.com/tutorials/re-programming-the-lilytiny--lilytwinkle" rel="nofollow" >https://learn.sparkfun.com/tutorials/re-programming-the-lilytiny&ndash;lilytwinkle</a> ].</p>Customer #511519 on DEV-11590 - LilyTwinkle ProtoSnapCustomer #511519urn:uuid:deee8808-5e34-5228-e24e-f2387fd1e36a2014-02-11T05:37:07-07:00<p>Thanks. So I need to first find the current I want and then find the forward voltage in the datasheet graph. Then I can calculate the resistor value. Since the resistor on the LED board is known to be 100 ohm, I will have to find which current and voltage pair that give a 100 ohm resistor. Correct?</p>
<p>3 mA give approximately 2.7 V forward voltage according to my interpretation of the diagram. This give (3-2.7) V / 3 mA = 100 ohm resistor.</p>
<p>So this means that when the battery (actually the AVR output pins) are at 3V, the LEDs get 3 mA given this LED datasheet and the 100 ohm resistor.</p>
<p>Correct?</p>Kamiquasi on DEV-11590 - LilyTwinkle ProtoSnapKamiquasiurn:uuid:9bb83354-9409-7a88-0141-10171e0d93ab2014-02-10T15:51:18-07:00<p>That comment is not entirely accurate. An LED&rsquo;s forward voltage is far more of a curve than that of, say, a zener diode.</p>
<p>Specifically, if you check out the <a href="https://www.sparkfun.com/datasheets/DevTools/LilyPad/APT3216QWF-D.pdf" rel="nofollow" >datasheet for the white LED used in on the LilyPad board</a> and scroll down to page 3, you&rsquo;ll find a current vs voltage graph there. You can see there that it&rsquo;ll work at 3V, but instead of about 20mA current you get 10mA current. According to the graph next to it, the relative luminous intensity vs current one, you&rsquo;ll see that they claim it will basically be about half as bright.<br/>
( As an aside, the datasheet for the battery itself claims it&rsquo;ll hover a bit above 3V for the first bit of the discharge curve anyway, and sits a fair bit below that afterward, further affecting the above. Suffice it to say, it&rsquo;ll light up - just less bright than it would if you actually applied 3.3V directly tot he LED. )</p>Customer #511519 on DEV-11590 - LilyTwinkle ProtoSnapCustomer #511519urn:uuid:4ce629ed-ff5e-8eda-cda5-09b087f4d0262014-02-10T14:40:52-07:00<p>One of the comments for the white LEDs say &ldquo;You can definitely run these without a LilyPad. But note that the forward voltage on these white LEDs is 3.3V, so your power supply will need to be higher than that.&rdquo;</p>
<p>How does the ProtoSnap - LilyTwinkle work with a 3V coin cell battery if the LEDs require more than 3.3V power supply?</p>Dia on DEV-11590 - LilyTwinkle ProtoSnapDiaurn:uuid:abe0ff22-23eb-3306-63c1-85effe9d3bc52013-10-09T09:18:00-06:00<p>Very close. DEFINITELY remove battery, and I&rsquo;d also change it to hand-wash. If you&rsquo;re machine-sewing your traces, the stitching will be secure enough for machine washing, but it&rsquo;s rough on the components, and will put too much strain on the connections between traces and components, which have to be hand-sewn.</p>
<p>PS- Would LOVE to see what you&rsquo;re making!</p>nsayer on DEV-11590 - LilyTwinkle ProtoSnapnsayerurn:uuid:0d5d2976-000a-52c5-faf2-47b4714a70bc2013-10-08T19:31:34-06:00<p>What modifications would one make to a garment&rsquo;s care instructions when modifying it to include stuff like this?</p>
<p>In other words, if you take a T-shirt, and then sew one of these sets into it to add a twinkling light effect to whatever the T shirt design is, then what would the care instructions tag be?</p>
<p>I&rsquo;m guessing:</p>
<p>Remove battery before washing. Machine wash warm, gentle cycle, air-dry - do not tumble, do not dry clean ?</p>MikeGrusin on DEV-11590 - LilyTwinkle ProtoSnapMikeGrusinurn:uuid:51b5fb37-6a82-a95b-87f3-a505b08b4f872013-07-17T11:28:25-06:00<p>It works here, are you still having issues?</p>MikeGrusin on DEV-11590 - LilyTwinkle ProtoSnapMikeGrusinurn:uuid:4e683e5b-f92d-054c-6a98-b2d47586ea0b2013-07-17T11:27:34-06:00<p>The &ldquo;Proto&rdquo; in &ldquo;Protosnap&rdquo; is meant to convey that you can fully test out your circuit <em>before</em> snapping it apart to be sewn into a project; something that&rsquo;s difficult to do otherwise. And sorry that the ISP pins aren&rsquo;t easier to use; it was a tradeoff against getting the board this small. Tip: sewing the board in chip-side down makes the programming pads easier to access, and using a <a href="https://www.sparkfun.com/products/11591" rel="nofollow" >pogo adapter</a> makes it a piece of pie. Cake. Your choice.</p>relaxing on DEV-11590 - LilyTwinkle ProtoSnaprelaxingurn:uuid:260df344-6d85-a17e-a0bd-a440be7c97fb2013-07-16T15:16:19-06:00<p>Considering the unit is meant to be used as-is, pre-programmed, what can you &ldquo;proto&rdquo; with this?
They could have at least made the ICSP headers friendlier to access&hellip;</p>Customer #227002 on DEV-11590 - LilyTwinkle ProtoSnapCustomer #227002urn:uuid:cda3bf00-e1c4-b5ff-40f7-90298e5e53bf2013-07-16T09:57:54-06:00<p>Just a note, the E-Textile Basics link in the Documents section doesn&rsquo;t work.</p>